Observer-based local torque optimization in redundant manipulator

In this paper, a local torque optimization strategy for a redundant manipulator based on observer is proposed. The calculation of the torque-optimizing controller becomes more complicated as the number of degrees-of-freedom increases because a pseudo inverse Jacobian matrix is generally used and the controller needs to calculate dynamical torque. To resolve this problem, the disturbance observer is applied to the redundant manipulator to simplify the controller calculation. Then, the torque-optimizing controller is realized without much effort required for calculating the null space term and dynamical effects. Furthermore, we find that the good performance of the workspace position response is obtained in the proposed controller. The validity of the proposed method is confirmed by the numerical and experimental results in the 3-link planar redundant manipulator.